1. Department of Materials Science and Engineering; National Chung Hsing University; Taichung 40227 Taiwan
2. Innovation and Development Center of Sustainable Agriculture; Research Center for Sustainable Energy and Nanotechnology; National Chung Hsing University; Taichung 40227 Taiwan
3. School of Materials Science and Engineering; Georgia Institute of Technology; Atlanta GA 30332 USA
4. Beijing Institute of Nanoenergy and Nanosystems; Chinese Academy of Sciences; National Center for Nanoscience and Technology (NCNST); Beijing 100083 P. R. China